24. Think again

The only Democratic Presidents who were running for re-election during a bad economy in the last 100 years besides Obama were FDR and Jimmy Carter. FDR won, Carter lost, so you can't really say that "conventional wisdom" says that a Democratic President can't be re-elected during a bad economy.

On the other hand, the party in power almost always loses seats in mid-term elections. For more than 100 years, it has been EXTREMELY hard for the sitting President's party to buck this trend, as the table in this article clearly demonstrates: